Example word count

Here is an example of how word count is performed using lua-mapreduce.

example/task-file.lua is a sample task-file for work count which implements following functions.

Server required functions:

1. taskfn: It reads the source and creates the map of the tasks. E.g For word count, it reads the all file with .lua from current directory and creates a map with key as a file name and content as a value.

	mr.taskfn = function()
		--logger:debug("Getting map task")
		local tasks = read_source()  -- read source is utility function defined to read data source
		for key, value in pairs(tasks) do
			coroutine.yield(key, value)
		end
	end

Here read_source() is a local function defined as below. NOTE: it uses luafilesystem (lfs) module to read the files

	local function read_source()
	  --local file_path = system.pathForFile( "*.lua", lfs.currentdir() )
	  local file_path = lfs.currentdir()
	  --logger:debug("Current directory path:" .. file_path)
	  local source_table = {}
	  for file in lfs.dir(file_path) do
	    if(string.find(file, ".lua") ~= nil) then
		--	logger:debug("File name:" .. file_path .. "/" .. file)
			local c = read_file(file_path .. "/" .. file)
		--	logger:debug("file:" .. file .. ", length:" .. #c)

			if( c ~= nil) then
				source_table[file]=c
			end
		end
	  end
	  return source_table
	end

2. finalfn : How to output final result. Here it prints on the console.

    mr.finalfn = function (results)
		print("Final results of the task:")
		for key, value in pairs(results) do
			print( key .. ":" .. value)
			coroutine.yield()
		end
	end